Magic sysrq key


usually ALT-PRINTSCREEN on x86
BREAK on serial console
often disabled on distributions
echo "1" > /proc/sys/kernel/sysrq

It can:
sync data to disks					s
remount partitions read only				u
reboot the machine					b
power the machine off				o

turns off keyboard raw mode and puts it in XLATE	r
dump the cpu registers and flags			p
list tasks and some useful information about them	t
kills of a process on the current console		k
send SIGTERM to everything except init			e
send SIGKILL to everything except init			i
send SIGKILL to everything including init		l
change the console loglevel				0-9